Tehran is the capital and largest city of Iran and the largest city in Tehran Province. With a population of around 9 million in the city and around 16 million in the larger metropolitan area of Greater Tehran, Tehran is the most populous city in Iran and Western Asia, and has the second-largest metropolitan area in the Middle East, after Cairo. It is ranked 24th in the world by metropolitan area population. Most of the population are Persian, with roughly 99% of them speaking the Persian language, alongside other ethnolinguistic groups in the city which became Persianized and assimilated. Tehran is served by Imam Khomeini International Airport, alongside the domestic Mehrabad Airport, a central railway station, Tehran Metro, a bus rapid transit system, trolleybuses, and a large network of highways.
